# Temperature's effect on humidity



## Suzza (Mar 18, 2010)

This is for everyone wondering whether or not the temperature you store you cigars at effects the humidity and moisture content of your cigars. I've know there's been dispute between "The humidity is what the hygrometer reads" and "Lower temps need higher humidity". Well here's the answer courtesey of Doc at StogieFresh.com!


Hi Chris, 


Great to hear from you, amigo. Thanks for taking the time to contact me. Your question is very interesting and also very problematic because of the differences between absolute and relative humidities and the relationship between temperature and humidity. 


The amount of water vapor in a sample of air, usually expressed as relative or absolute humidity. Absolute humidity is the total mass of water in a given volume of air, expressed in grams per cubic centimeter. A sample of air of a given temperature and pressure can hold a certain amount of water, above which point (known as the dew point) saturation occurs. Warmer air is able to hold more water vapor than cold air and so, for the same pressure, has a higher absolute humidity.

Relative humidity is defined as the ratio of the partial pressure of water vapor (in a gaseous mixture of air and water vapor) to the saturated vapor pressure of water at a given temperature. In other words, relative humidity is the ratio of the current absolute humidity to the highest possible absolute humidity (which depends on the current air temperature). 


So, regarding your question, at 65%RH and at two different temperatures (60° F and 70° F) there would be more water in the air per kilogram (i.e., absolute humidity) in the warmer of the two temperatures. Even though your hygrometer says 65%RH, there will be more moisture within a given space at the higher of the two temperatures.


That said, I have seen the "relative" vs "absolute" humidity discussions surface on many different boards. They always tend to generate a lot of heat, and very little light...

The relationship of vapor pressures, absolute and relative humidities are based on measurements within an enclosed and/or controlled system (theoretically or otherwise). However, in the real world, we don't allow the conditions to get to extremes and there are several factors that affect the system, like humidor construction, type and thickness of humidor outer walls, thickness of Spanish cedar, active/passive humidifiers, and types of humidification source.

In fact, the goal of a well-conditioned humidor is to preserve an environment that is not too hot and not too humid, and yet not too cold and not too arid. If the humidor is doing its job, the internal environment of the humi will be temperate and thus, it is difficult to make comparisons to very cold, very hot, very dry or very moist environments. The humidor is a dynamic system with plenty of push and pull.

Every time I open my humi, of course, the internal environment gets reset as all the air whooshes out. This is where active humidifiers systems come in handy. They can increase the rate at which the humidor re-humidifies itself. On the other hand, since an active humidifier only puts moisture into the environment, it can actually work against you under certain environmental conditions. Further, the Spanish cedar inside the humidor changes the dynamics of the molecules in the box, and so do polymers and RH beads.

At 60 degrees, the air inside your humidor will contract (i.e., have a less capacity for holding moisture) and, at a %RH of 68, the cigars will actually become drier. That's because at lower temperatures, even though the RELATIVE HUMIDITY seems right, the ABSOLUTE HUMIDITY is lower. Usually, when temperatures are lower, you want to see a higher relative humidity. Therefore, to prevent cigars from drying out in colder temperatures, make sure your humidifier is well charged.

When the temperature rises the air expands and it's ability to hold moisture increases. At 80 degrees your cigars are in danger of getting too wet. You want your relative humidity to be lower (otherwise your cigars will become wetter, even though the relative %RH is 68.)

70%RH and 60 degrees = drier cigars
70%RH and 80 degrees = wetter cigars

That's why I recommend a temperature/RH% goal of around 70/70, or in a range between 65-72%RH and 65-72 degrees. This provides us some wiggle room and allows a certain margin of error. If you like drier cigars you can fudge toward the bottom of the range and if you like your cigars a little more humid, then you can shoot for the upper end of the range.

It's really a sticky debate and I try to avoid the discussions for the most part. Intellectually it is an interesting discussion, but practically speaking, I just tell people to try and keep their temperature and humidity within a 'safe' range. The real test is how your cigars look, feel and smoke.


I hope that helps somewhat. Take care and keep in touch.


Doc


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## jimjim99 (Jan 25, 2009)

Suzza, your the man. I had a tat cab maduro just now and it was at around 62% and 84F. It smoked very hot. 
This question was bothering me the whole day. GREAT POST!


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## Mante (Dec 25, 2009)

I recently got reamed on another forum over exactly this topic. The case I stated was the same that you have posted but many senior members there took me to the cleaners over it. I totally agree with Doc but am saying no more on this subject on any forum. Nice work Chris. (Waiting to get back handed even now! LMAO)


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## Cigary (Oct 19, 2007)

I can tell you horror stories over this and clinical meterologists as well as practicing scientists will explain all sorts of conditions about RH and temperatures. I keep beads in my humis and they keep them at the RH I want them to...I sometimes have my house get up into the upper 70's and maybe even touch 80 degrees at times and my humidor stays a rock solid 67. Regardless of the outside environment as long as it's not warm my humidors ( all 11 of them ) stay within the 67RH markers. I have studied all of the relevant information on the perfect setting of 70/70 and what happens if the temperature goes above 70 and what happens to the RH inside....as long as the inside of my humidor stays within the marker I want it at I stopped givin a shyte about outside temps as long it isn't over 80. I don't have beetles and my cigars are happy campers. The day I started using beads is the day I stopped worrying about temperatures effects on the humidity in my humidors. This paragraph says it all:

*It's really a sticky debate and I try to avoid the discussions for the most part. Intellectually it is an interesting discussion, but practically speaking, I just tell people to try and keep their temperature and humidity within a 'safe' range. The real test is how your cigars look, feel and smoke.*


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## Herf N Turf (Dec 31, 2008)

Cigary said:


> I can tell you horror stories over this and clinical meterologists as well as practicing scientists will explain all sorts of conditions about RH and temperatures. I keep beads in my humis and they keep them at the RH I want them to...I sometimes have my house get up into the upper 70's and maybe even touch 80 degrees at times and my humidor stays a rock solid 67. Regardless of the outside environment as long as it's not warm my humidors ( all 11 of them ) stay within the 67RH markers. I have studied all of the relevant information on the perfect setting of 70/70 and what happens if the temperature goes above 70 and what happens to the RH inside....as long as the inside of my humidor stays within the marker I want it at I stopped givin a shyte about outside temps as long it isn't over 80. I don't have beetles and my cigars are happy campers. The day I started using beads is the day I stopped worrying about temperatures effects on the humidity in my humidors. This paragraph says it all:
> 
> *It's really a sticky debate and I try to avoid the discussions for the most part. Intellectually it is an interesting discussion, but practically speaking, I just tell people to try and keep their temperature and humidity within a 'safe' range. The real test is how your cigars look, feel and smoke.*


Thank you, Gary. Pretty much what I was gonna say, only much nicer.


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## bigslowrock (May 9, 2010)

I'm really glad to see this and another thread pointing to some CA article. It was pretty maddening to me (being the science/engineer type) to keep seeing all these RH and temps thrown around as a noob. 

Still like most things that are based on perception such as taste, smell, draw, it will always be partly an art with no 100% scientifically right answer on how to store and age the smokes.


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## asmartbull (Aug 16, 2009)

Great topic

But all this sh*t can drive me crazy.

Since I am a simple man arty:

CC'[email protected] 60 RH
[email protected] RH

and I try to keep temps 65-70

Screw it,,,let's smoke


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## Mante (Dec 25, 2009)

asmartbull said:


> Great topic
> 
> But all this sh*t can drive me crazy.
> 
> ...


LMAO. :clap2::clap2::clap2::whoo::whoo::whoo: :dude::dude::dude: :beerchug:


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## jaq6plus (Jun 7, 2006)

The Doc talks very sound physics. The air pressure is another limiting factor but at that point it gets horribly complicated. The one thing we should draw from this is that as well as a hygrometer in the humidor we should have a thermometer nearby allowing you to adjust the RH setting to the temperature around the humi.


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## Mante (Dec 25, 2009)

jaq6plus said:


> The Doc talks very sound physics. The air pressure is another limiting factor but at that point it gets horribly complicated. The one thing we should draw from this is that as well as a hygrometer in the humidor we should have a thermometer nearby allowing you to adjust the RH setting to the temperature around the humi.


My god, your going where I didnt dare. LOL. 


> we should have a thermometer nearby allowing you to adjust the RH setting to the temperature around the humi


Unless we use a sealed environment like a wineador.

Nicely done with the Barometric pressure comment as well as I didnt want to throw that little curve ball in either, for previously stated reasons.:clap2::dude:


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## Dando (Jul 16, 2010)

Thanks Suzza and Doc for this info!

As I am just starting out I had been thinking about how to protect my cigars. My humidor (300 ct. - 3,700 cu. in.) will be in my garage (I've been banished there). 

In the Summer the garage will be:
70F - 80F 60% - 80% humidity. 

In the Winter the garage will be:
50F - 60F 10% - 30% humidity.

Doc says:
70%RH and 60 degrees = drier cigars
70%RH and 80 degrees = wetter cigars

I'm the type of person who will check the readings 10 times a day. So after about 30 minutes of trying to workout a temperature vs. humidity sliding scale :frusty: I think I'm just going to get a wine cooler which will regulate the inside temperature no matter the outside temperature. 

I'll add heartfelt beads at 1.5 x the cu. in. interior, some Spanish cedar trays and be done with it. Less stress on the cigars and less stress on me!

I wonder how my coffee would taste if I kept it in that humidor?

Thanks again Suzza and Doc, this really jump started my day. :tu

Dando


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## bigslowrock (May 9, 2010)

Tashaz said:


> Nicely done with the Barometric pressure comment as well as I didnt want to throw that little curve ball in either, for previously stated reasons.:clap2::dude:


Why?

Note to anyone storing their cigars on the top of a mountain or inside the storm wall of a hurricane - you will need to run a higher RH than normally proposed on the site


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## Cigary (Oct 19, 2007)

Herf N Turf said:


> Thank you, Gary. Pretty much what I was gonna say, only much nicer.





asmartbull said:


> Great topic
> 
> But all this sh*t can drive me crazy.
> 
> ...


I can be as AR as the next guy when it comes to stuff like this but after seeing what beads can do I'm convinced as to what they do for regulating humidity. We can hypothesize all day long but when you get to the end of the meeting.....beads.


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## Cigar Runner (Sep 30, 2009)

Shucks, i'm going to have to light up a cigar & think this through :scared:


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## chingachguk (Jun 15, 2010)

After reading all this I got worried for my cigars and had to check on them. Sure enough, one of them in particular was clearly a little chilly. I'm warming it up right now...


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## Mante (Dec 25, 2009)

bigslowrock said:


> Why?
> 
> Note to anyone storing their cigars on the top of a mountain or inside the storm wall of a hurricane - you will need to run a higher RH than normally proposed on the site


Oh bloody hell! Barometric Pressure changes air density hence altering absolute humidity, water being uncompressable. Note to self, do not place std humidors outside in a hurricane on a humid day when the barometric pressure is below 990. Above that should be ok if the sun is shining, the dew point is above 10F, the AppTemp is 2 degrees higher than ambient and the wet bulb is flowering.:der:


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## Benaj85 (Feb 5, 2010)

Where is the my head is spinning smilie?


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## e-man (Jan 5, 2009)

Relative humidity is the important measurement. If the TOTAL amount of water in the air was important, then our hygrometers would display that value instead. 

These charts clearly demonstrate that the air is CAPABLE of holding more moisture at higher temps, and nothing else. Being a RELATIVE measurement, it takes more water vapor to achieve 70% saturation at a higher temp than at a lower temp. The fallacy is the ASSUMPTION that the additional water in the air directly affects the total moisture content of the cigar. 


Example:

Lets say you have a cigar stabilized at 70%. We all know that if the rH is lower than 70%, the cigar will release moisture until it equalizes with the air. If the air has a higher rH, then the cigar takes on moisture. It's that simple. It doesn't matter what the temp is. A 70% cigar in 70% air will not take on or lose any moisture. So long as the air and cigar have the same temp, the same relative humidity will keep the same total moisture content in the cigar.




I was also misled by these charts until another BOTL showed me a scientific paper on the subject. It used an example of the lumber industry in Washington State. Lumber is put into an oven to reduce the total moisture content of the wood. The total moisture content of the air hasn't changed, but the increased temperature reduces the rH, thereby causing the wood to release it's moisture.

Once cured, any change in total moisture content can cause the finished lumber to warp, but the rH in that part of the country is so high that the wood will quickly re-absorb the moisture and climb out of tolerance. The solution is to keep the wood in a temperature controlled warehouse. The total moisture content of the air is the same inside and outside the warehouse. However, they increase the temperature of the warehouse to lower the rH of the air, thus prohibiting the lumber from absorbing additional moisture. This example demonstrates that the total amount of moisture in the air does not directly affect the total amount of moisture in the wood. The relative humidity is the mechanism at play. If a multi-billion dollar industry can operate using this simple concept, then what more proof do you need?



The additional moisture in a warmer climate DOES have some effect though. More water vapor in the air, means that there is more moisture available to EXCHANGE. A glass of water will evaporate faster in 100 degree temps than 50 degree temps...right? If your cigars are absorbing the moisture from the air, a higher temp allows your humidifier to replace it faster, thus reducing the time needed to equalize. If your cigars are wet, the higher temp allows the moisture to leave the cigar quicker and be absorbed by the humidifier. Additionally, higher temps increase the metabolism of micro-organisms, which will speed up the secondary fermentation process. Therefore, higher temps means your cigars are ready to smoke faster.


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## asmartbull (Aug 16, 2009)

Tashaz said:


> Oh bloody hell! Barometric Pressure changes air density hence altering absolute humidity, water being uncompressable. Note to self, do not place std humidors outside in a hurricane on a humid day when the barometric pressure is below 990. Above that should be ok if the sun is shining, the dew point is above 10F, the AppTemp is 2 degrees higher than ambient and the wet bulb is flowering.:der:


I knew you would take the bait
Now
You think your so damn smart.......

:boink:


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## Mante (Dec 25, 2009)

asmartbull said:


> I knew you would take the bait
> Now
> You think your so damn smart.......
> 
> :boink:


I'm not smart, a dumbass! I plead the fifth! Oh crap, thats only in the US. Ok, to use much quoted term by politicians here "I Cant Recall!" LOL. :spank:


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## xJaCkSlApx (May 7, 2010)

very helpful thank you


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## asmartbull (Aug 16, 2009)

Since we are beating this horse, I have a stupid question
(Early Onset Alzheimer) ,
that I am sure my friend Warren can answer....or anyone else.

If a *Sealed *container reads 70/70 .......
Temp rises to 75. What does the RH do?
Now the container is in the same place. It has not gone to a hurricane, tropical depression, climbed a mtn, ect.

Thanks, gents.....


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## Mante (Dec 25, 2009)

> I totally agree with Doc but am saying no more on this subject on any forum


Due to internal bruising and a recurring limp I restate my original post. :crutch::crutch::crutch:


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